Hydraulic mechanism for actuating an engine valve with variable timing



March 19, 1957 R. MILLER HYDRAULIC NECHANISN FOR ACTUATING AN ENGINE:VALVE WITH VARIABLE TIMING med Nov. 1e, 195s niteci States PatentHYDRAULIC MECHANISM FOR ACTUATING AN ENGINE VALVE WITH VARIABLE'I'IlVIING Ralph Miller, Milwaukee, Wis., assigner to NordbergManufacturing Company, Milwaukee, Wis., a corporation of WisconsinApplication November 18, 1953, Serial No. 392,881

8 Claims. (Cl. 12S-90) This is a continuation, in part, of applicationSerial No. 242,372,'led August 17, 1951.

My invention resides in the field of internal combustion engines and isan improvement on prior mechanisms for actuating and timing the openingand closing of an engine valve. More specically, my valve actuatingmechanism varies the timing of the valve in accordance with a specicfactor of the engine.

My invention is a hydraulic mechanism of a new and novel type forvarying the time of any engine valve, although I have shown anddescribed it as specifically applied to a particular type of engine anda particular valve arrangement. Specilically, I have illustrated myinvention in connection with a uniow scavenging two-stroke cycle enginewith a :series of exhaust ports around the cylinder Wall and an intakeport in the cylinder head, the exhaust ports being opened and closed bythe piston.

A primary object of my invention is a pneumatic or hydraulic control andactuating mechanism for an engine valve to control the timing of thevalve in accordance with the load on the engine.

Another object of my invention is a pneumatic or hydraulic control andactuating mechanism for an engine valve which responds to variations inthe pressure of the air supplied to the engine from a scavenging and/orsupercharging blower. n f Other objects will appear from time to time inthe en suing specification and drawings in which:

Figure l is a diagrammatic view of a cylinder of a twostroke cycleengine, partly in section, and a hydraulic or pneumatic mechanism foractuating the engine valve, partly in section, with various otherassociated mechanism;

Figure 2 is an enlarged View of the actuating plunger shown in Figure l;and

v Figure 3 is a section taken along lines 3 3 of Figure 2. i In Figurel, a two-stroke cycle engine is illustrated. A cylinder has a piston 12which is mounted for reciprocation in it in a conventional manner. Aplurality of exhaust ports 14 are positioned around the cylinder walland are enclosed by the conventional exhaust manifold 16. IThe cylinderhead 18 has an inlet port 20 which is controlled by an inlet valve 22.

The hot exhaust gases from the cylinder exhaust through the ports 14into a conventional turbocharger, indicated generally at 24, the gasesdriving a turbine 26 which, in turn, drives a supercharging blower 28.The hot gases exhaust from the fan by an outlet 30.

The supercharging blower 2S draws in air through an inlet 32 and, afteri-t is compressed to an elevated temperature and pressure, it is carriedthrough an intercooler 34 and through a conventional inlet manifold 36to the inlet port 20 and to thecylinder. The intercooler substantiallyreduces the temperature of the air by withdrawing the heat ofcompression from it'that was generated in the super charging blower. Thecooling lluid for the intercooler en# ters through an inlet, indicatedgenerally at 38, and exits through an appropriate connection 40. Y

ice

The inlet Valve 22 has a valve stem 42 which slides in a valve stemguide 44. The upper end of the valve carries a ring member 46, and aconventional valve spring48 biases the valve closed.

A cage 50 is bolted to the top of the cylinder head around the valvestem and the spring 48. The upper part of the cage 50 has a cylinder 52,and a plunger 54 slides in the cylinder and engages the top of the ringmember 46 on the valve stem. The cylinder is closed at the top by a plug56. Fluid is conveyed to the hydraulic cylinder 52 by an appropriatepipe 58 and is discharged from it by van overflow spill pipe 60.

Fluid is pumped through the pipe 58 to the cylinder 52 by an actuatingmechanism, indicated generally at H. Variable quantities of tluid arepumped through the pipe 58 by the actuating mechanism to force theplunger 54 down and open the inlet valve 22. The opening excursion ofthe valve 22 is determined by the overow spill pipe 60, it beingunderstood that the spill pipe leads back to the low pressure side ofthe system. As long as iiuid is being forced through the pipe 58 to thecylinder 52 by the actuating mechanism H, the valve 22 will stay openand the excess lluid will llow ol through the spill pipe 60.

The actuating mechanism H includes a pump 62 and a pump controllingmechanism 64. The pump has a housing 66 with a chamber 68 which isconnected to the pipe 58 leading to the cylinder 52. A low pressuresource of supply 70 for the fluid communicates with the chamber 68through a passage 72. This passage is closed and opened by the surfaceof a plunger 74 which is reciprocably mounted in the chamber. The lowerend of the plunger rides on a crosshead '76 which carries a camfollowerf78. The follower rides on a cam on the conventional engine camshaft 32, the direction of the rotation of the cam shaft beingcounterclockwise, as shown.

A gear 84 carried by the plunger is engaged and rotated by a rack 86 onthe outside of the plunger housing, so that movement of the rack rotatesthe plunger. The rack is connected at one end to the stem 88 of a uidpiston 90 in the housing 92 of the hydraulic actuating mechanism 64.

The housing 92 of the hydraulic mechanism has a chamber which is dividedby a wall 94, the piston being in the left compartment 95. An air piston96 is positioned in the right compartment 97 of the housing andstraddles a plurality of openings for a group of central passages in thepiston stem 88. A spring 98 bears against the wall 94 in the housing andbiases the air piston toward theV opposite end of the housing. A collar100, positioned on the end of the stem to limit the travel of the airpiston 96, is positioned in a chamber 101 dened by a housing 102 mountedon the air piston.

The stem 88 has a plurality of longitudinal uid passages with ports onits surface. Fluid is discharged through an appropriate connection 104in the right compartment 97 on the left side of the air piston. One ofthe control passages 106 in the piston stem conducts uid from an outsidechamber 108 to a chamber 110 in the air piston. Another one of thecentral passages 112 in the st-em leads fro-m the right side of .thelluid piston 90, and the other central passage 114 leads from the leftside of the piston 90, and their other ends open into the rightcompartment 97 and are controlled by the air piston 96. Passages 115 inthe air piston communicate the chamber 101 with the left side of the airpiston.

The discharge pressure from the supercharging blower 28 is conveyedthrough an appropriate pipe 116 to the right compartment 97 on the rightside of the air piston. As this pressure varies, it tends to move theair piston. As the pressure increases, the air piston moves to the leftcompressing the spring 98, and as the pressure decreases,

r the spring moves the air piston bacl to the right. Move-f ment of theair piston controls the communication that is established between thevarious chambers through the central passages 106, 112, and 114, asexplained herein below.r A source of high pressure hydraulic uid 118communicates with the chamber 1%8 and the passage 106. This source ofduid could be the engines lubricating system.

The plunger 74 has helixes formed on its upper surface, as shown indetail in Figures 2 andY 3. The upper helix 1,20 forms closing edge forthe passage 72 and the lower helix 122V forms an opening edge. As theplunger moves up, the helix 12.0V closes the passage 72 and traps duidin the chamber GS. This duid is forced through the pipe 58 and opens thevalve 22. The chamber 68 communicates with a.V groove 124 cut into Vtheplunger through a central passage 126 so that when the lower helix 122opens the passage 72, the pressure in the chamber 68 will be relievedthrough the central passage:

As shownin Figurel 2, the two helixes are adapted to close and open theport 72 at different times during the engine cycle, vdepending upon thepositionV tof which the plunger has been rotated 'by the actuatingmechanism H. IfV the plunger has been turned so that thelower ends ofthe helixes120 and 122 are aligned with the passage 72, uid will not bevconveyed to the chamber 52 until relativelyY late during the enginecycle, and thevalve 22 will openV and closelate.v If ythe upper ends ofthe helixes are aligned with the passage 72, tluid will be conveyed tothe chamber' 52 early in the engine cycle, and the valve will open andclose early. VBecause of the helical contour of theppeniugarrd closingedges on the plunger, the time of opening and closing of the valve 22can be adjusted to any'desired conditions and this adjustment is edectedby theactuating'mechanism H in accordance with the pres- Y 'su-re oflthe supercharging air.

The use, operation, and function of my inventionare as: follows Thepressure of the supercharging air is conveyed through the pipe 116 tothe'compartmen-t 237 on the right side of the vair piston. As the loadincreases, this pressure will increase and the air piston 96 will moveto the left compressing the spring 98. This left position of the airpiston places the source ofthe uid 118 in communicationwith the passage112 and the right side of the iluid piston 90 through the chamber 1&8,passage 10d, chamber 110, and passage 112. This causes the stem SS ofthe pistonvt'oemoveV to the left in Figure l, and the lower end of theVhelixes will control the port 72. The discharge connection 104 is placedin communication with ythe left side ofthe uid pistonY through passages1155,. chamber 101, and passage 114, and the time of opening andclosing' of the valve-22 will be retarded during the engine cycle.

When the: lo'ad decreases, the pressure of the air conveyed through thepipe 115 to the chamber 118 willA decrease, and the spring 98 will forcethe air piston 96 to the` right.

This places the source of the duid 118 inV communication with the leftside of the duidA piston throughv the chamber 198, passage 166, chamber119 and the passage 114. At the same time, the discharge conduit 104will `be placed in communication with the right side ofthe iuidV piston90 through'the passage 112. This forces the iuid pistou and its stem S8to the right, and

aligns the upper end of the helixes of the plunger 74 with the. port 72.Thus, the opening and closing of the valve 22 will be advanced duringthe engine cycle.

The position of the air piston 95 controls which side of the uid piston90 is placed in communication with the high pressure source of fluid sothat the tluid piston. 90 will shiftits stemA 88 and the rack 86 ineither one direction or the other. The position lof the air piston iscontrolle'd by its` spring 98 and 'the pressure of the air from thesupercharger 24. Shiftingof the rack aligns a different portion of thehelix on the plunger withthe port 72, and the-'timing of the valve 22will accordingly be varied duringlrthe engine cycle. Y

Even though I have shown the closing edge V120 and the opening edge 122as approximately parallel, it should be understood that Ithe, closingedge coul-d be perpendicu lar to the axis of the plunger, so that thetime of closing of the valve 22 would be approximately constant regarduless of the load on the engine, but the time of opening would be variedby the helical opening edge 122. In a similar manner the closing edge120 could be a helix but it would not necessarily have to be parallel tothe opening edge 122. These two edges lcould diverge downwardlyorupwardly so that the period of time that the valve 22 stayed open wouldnot be constant as the load varied,jbut at the same time both theftimeof opening and the time of closing of the valve wouldvary as the loadchanged. It should be understood that the closing and opening edges 12oand 122 on the plunger 74 can be designed in any convenient andwell-known manner to produce any desired timing of the valve. A

While I have shown and Adescribed the preferred form of my invention, itshould be understood thatV various' modications, Valternations, andlchanges can be made without departing from the functional theme of myin-4 vention. For example, I have stated that a high presL Vsure sourceof uid is used to actuate the mechanism H, and it should be understoodthat this could` be oil, high pressure air, or any high pressure fluidthat is read'- ily available. In the claims, the term fluid should beinterpreted to mean any one of these forms. I therefore desire that theinvention be unrestricted exceptY as bythe appended claims.

' I claim:

l. In an internal combustion engine cylinder having a port, an enginevalve for controlling the port, yielding means biasing the valve toclose said port, a hydraulic power cylinder, a plunger movable thereinadapted to overcome the yielding means and open the valve, a pumpcylinder, -a duct joining the pump and the power cylinders,'aV plungerin the pump cylinder, means responsive to engine operation fordisplacing it to supply hydraulic pressure to open the engine valve,means for supplying air under pressure to the engine cylinder, and meansresponsive to variation in the pressure of said air foi, varying thetime when the engine valve is operated.

2. In an internal combustion engine cylinder having a port, an enginevalve for controlling the port, yielding means biasingthe valve to closesaid port, a hydraulic power cylinder, a plunger movable therein,adapted to overcome the yielding means and open the valve, a pumpcylinder, a duct joining the pump and the power cylinders, a plunger inthev pump cylinder and means' responsive to engine operation fordisplacing it to supply hydraulic pressure to open the engine valve,means for supplying air underY pressure to the engine cylinder and meansresponsive to variation in the pressure of said air Vfoi varying thetime when the engine valve is closed, a

port in the hydraulic power cylinder adapted to be opened by the plungerwhen the engine valve is opened, the resistance to passage of hydraulicuid through said portV being adapted to hold the engine valve open asthe plunger Vis moved by the engine toward valve opening position. Y

3. In an internal combustion engine cylinder having a port, an enginevalve for controlling the port, yyielding means biasing'it to close saidport, a hydraulic power cylinder, a plunger movablethereiu, adapted toovercomeV the yieldingmcans and open the valve, a pump cylinder, a ductYjoining the pump and the power cylinders, a plunger in the pumpcylinder, means responsive to engine operation for displacing it tosupply hydraulic pressure to open the engine valve,A and meansresponsivek to a variablek engine factor for varying theY timingV of thesuppliedhydraulic pressure.

v In an internal combustion engine, means'forsupply-i mitting air andhydraulic means forl opening it, includ-v ing a pump, means responsiveto variation in the pressure of the air supplied to the engine forvarying the cycle of pump operation.

5. In an internal combustion engine, an engine valve for admitting airand hydraulic means for opening it, including a pump, means responsiveto a variable engine factor for varying the cycle of pump operation,said means including a pneumatically operated Valve member controlled bythe factor, and a hydraulic piston responsive to the valve member.

6. The structure of claim 5 wherein t'ne pneumatically operated valvemember and the hydraulic piston are generally aligned.

7. In an internal combustion engine, an engine valve for admitting airand hydraulic means for opening it, including a pump, means responsiveto a variable engine factor for varying the cycle of pump operation,said means including a pneumatically operated valve member controlled bythe engine factor, and a hydraulic piston responsive to the valvemember, there being a pump plunger having a release port therein, thepiston being adapted to rotate the plunger to vary the time ofuncovering the release port.

8. The structure of claim 7 wherein the hydraulic piston andpneumatically operated valve member are generally aligned.

References Cited in the le of this patent UNITED STATES PATENTS2,174,526 Parker Oct. 3, 1939 2,447,267 Mock Aug. 17, 1948 2,565,681Fleck et al. Aug. 28, 1951 2,602,434 Barnaby July 8, 1952 2,621,640Reggio Dec. 16, 1952 2,670,595 Miller Mar. 2, 1954 FOREIGN PATENTS758,184 France Ian. 11, 1934 641,322 Germany Jan. 27, 1937

